LINER 2593699 - Caterpillar

System Operation Description:Use this procedure to troubleshoot suspect problems with the secondary circuit for the ignition transformers.This procedure covers the following diagnostic codes:
401-5 Ignition Transformer Secondary #1 : Current Below Normal
401-6 Ignition Transformer Secondary #1 : Current Above Normal
402-5 Ignition Transformer Secondary #2 : Current Below Normal
402-6 Ignition Transformer Secondary #2 : Current Above Normal
403-5 Ignition Transformer Secondary #3 : Current Below Normal
403-6 Ignition Transformer Secondary #3 : Current Above Normal
404-5 Ignition Transformer Secondary #4 : Current Below Normal
404-6 Ignition Transformer Secondary #4 : Current Above Normal
405-5 Ignition Transformer Secondary #5 : Current Below Normal
405-6 Ignition Transformer Secondary #5 : Current Above Normal
406-5 Ignition Transformer Secondary #6 : Current Below Normal
406-6 Ignition Transformer Secondary #6 : Current Above Normal
407-5 Ignition Transformer Secondary #7 : Current Below Normal
407-6 Ignition Transformer Secondary #7 : Current Above Normal
408-5 Ignition Transformer Secondary #8 : Current Below Normal
408-6 Ignition Transformer Secondary #8 : Current Above Normal
409-5 Ignition Transformer Secondary #9 : Current Below Normal
409-6 Ignition Transformer Secondary #9 : Current Above Normal
410-5 Ignition Transformer Secondary #10 : Current Below Normal
410-6 Ignition Transformer Secondary #10 : Current Above Normal
411-5 Ignition Transformer Secondary #11 : Current Below Normal
411-6 Ignition Transformer Secondary #11 : Current Above Normal
412-5 Ignition Transformer Secondary #12 : Current Below Normal
412-6 Ignition Transformer Secondary #12 : Current Above Normal
413-5 Ignition Transformer Secondary #13 : Current Below Normal
413-6 Ignition Transformer Secondary #13 : Current Above Normal
414-5 Ignition Transformer Secondary #14 : Current Below Normal
414-6 Ignition Transformer Secondary #14 : Current Above Normal
415-5 Ignition Transformer Secondary #15 : Current Below Normal
415-6 Ignition Transformer Secondary #15 : Current Above Normal
416-5 Ignition Transformer Secondary #16 : Current Below Normal
416-6 Ignition Transformer Secondary #16 : Current Above NormalThe ignition transformers initiate combustion by providing high voltage to the spark plugs. The positive output from the secondary circuit of the transformer is at the connection for the terminal of the transformer and the terminal of the spark plug. The transformers are located underneath covers at the top of each cylinder. Each transformer is grounded to the cylinder head via a mounting flange.
Illustration 1 g01057652
Ignition transformer and spark plug
(1) Mounting flange
(2) 3-pin connector
(3) Transformer
(4) Extension
(5) Secondary spark plug terminal
(6) O-ring seal
(7) Hole in the spark plug's precombustion chamber The secondary circuit of the transformer provides an initial 8,000 to 37,000 volts to the spark plug. This voltage ionizes the spark plug gap. This voltage is then reduced to about 1000 volts. The total duration of the spark is approximately 400 microseconds.The Electronic Control Module (ECM) can diagnose the primary circuit of the ignition transformers for open circuits and/or for short circuits. Secondary open circuits and short circuits will not directly shut down the engine. However, these conditions may lead to misfire which can cause lugging of the engine. Lugging of the engine can cause a shutdown.Logged diagnostic codes provide a historical record. Before you begin this procedure, use the Caterpillar Electronic Technician (ET) to print the logged codes to a file.Note: Ignition transformers from Electronic Ignition Systems (EIS) are not